Earlier quoted context omitted.
The internet sleuthing might just be smoke and mirrors. It's possible this guy already knew where the monolith because he knew the installer or is the installer. Either way, he's comes out looking good. Not sure which is more likely.
Eh there are whole communities of people who do stuff like this as a hobby. There's no particular reason not to believe it.
Merely raising the possibility that he could have gotten his information another way.
People who put up things like this often want them to get found.